25D/37D Gearmotors reverse mechanical input?

Hey all,

We have an application where we need a low RPM motor which will NOT take mechanical damage if forced backwards when fully stalled. Additionally when zero current is being sent to the unit it needs to be able to free spin.

I know steppers may be the more logical choice but we are considering using a straight brushed/brushless motor instead… The only issue is we need something in the sub 200 RPM range so were probabbly going to need a geared solution.

would love any input as to the practicality of using Pololu geared motors for this application…



We have not characterized our gearmotors in this regard and cannot really offer any specific advice about how they would perform long-term in such an application. Ultimately, this is something you would need to try out for yourself. In general, stalling a motor is difficult on it both electrically and mechanically, so you should probably avoid situations where more than 30% of the stall torque applied for a prolonged period of time (e.g. I would not try to backdrive it with the full rated operating voltage applied).

If you use a motor controller, you might be able to control the amount of motor resistance by switching between coast and brake mode using a PWM signal, effectively implementing variable braking. Please note, you could still damage the gears in the gearmotor while braking if you backdrive the shaft with enough force.

- Grant